Listen to Mozart : Piano Sonata No.17 In B Flat Major K.570 – III. Allegretto online. Mozart : Piano Sonata No.17 In B Flat Major K.570 – III. Allegretto is an Instrumental language song and is sung by Relaxing Mode. Mozart : Piano Sonata No.17 In B Flat Major K.570 – III. Allegretto, from the album Collection Of Classical Bedtime Music Mode When Sleeping 1, was released in the year 2025. The duration of the song is 6:00. Download Instrumental songs online from JioSaavn.